The aim of this study was to investigate the incidence and course of neutropenia following intravenous immunoglobulin (IVIG) therapy in children with idiopathic thrombocytopenic purpura (ITP).

From January 2001 to June 2006, fifty-four patients with ITP were enrolled in this study. Forty-two of 54 patients were treated with IVIG, while the other 12 were treated with anti-D immunoglobulin (Anti-D Ig). Post-treatment absolute neutrophil counts (ANC) were compared between patients who received IVIG and those who received Anti-D Ig. Comparison of post-treatment ANC between patients who treated with two different IVIG regimens (400 mg/kg/day for 5 days and 1 g/kg/day for 2 days) was also performed.

Pretreatment ANC were not significantly different between the two treatment groups. After treatment with IVIG, 32 out of 42 patients (76.2%) showed more than 50% decrease of ANC from the baseline. On the other hand, only 2 out of 12 patients (16.7%) showed more than 50% decrease of ANC from the baseline after treatment Anti-D Ig. No significant difference was observed in the decline of ANC between the first IVIG treatment (42 patients) and repeated IVIG treatment groups (7 patients). There was no statistical difference in post-treatment ANC between patients who treated with two different IVIG regimens. The neutropenia induced by IVIG had resolved spontaneously in 38 out of 39 patients (97%) after several days.

Neutropenia following IVIG administration may not be an uncommon finding in children with ITP. It seems to be transient and self limited.